Laundry complaints send a lot of people looking for a filter, and the equipment that helps depends entirely on which complaint you have. Stiff grey washing, orange staining and a chlorine smell in the fabric are three different problems with three different answers, and only one of them is actually a filtration job.
Stiff, grey, dull laundry is hardness
Hardness minerals react with detergent to form an insoluble residue that deposits in fabric, which is what makes washing feel stiff and look progressively duller. It also means more detergent is needed for the same result, since some of it is being consumed by the reaction rather than doing any cleaning. The USGS classifies hardness as dissolved calcium and magnesium, and no filter removes it: this needs an ion exchange softener, which is why laundry is one of the first things people notice after fitting one.
Orange or brown staining is iron
Iron in the supply oxidizes and deposits in fabric, and it sets permanently if the load is dried before the stain is treated. The fix is at the water: dissolved iron within a softener's limits can be handled by the softener, and heavier or oxidized loads need an iron filter ahead of it. In the meantime, do not use chlorine bleach on iron stained washing, because it oxidizes the iron and turns a faint yellow into a fixed brown, and use a rust removing laundry product instead.
Chlorine smell and fabric wear is a filtration job
This is the one a filter genuinely addresses. A whole house carbon filter removes chlorine from every tap including the laundry supply, which removes the smell from towels and bedding and is gentler on fibres and elastic over time. It is a point of entry stage rather than a laundry appliance, and it is worth fitting for the showers as much as for the washing. On a chloraminated supply, the unit must use catalytic carbon and adequate contact time or it will underperform.
What to fit, in order
Sediment filtration first, which protects the washing machine's inlet solenoids from grit, a genuine cause of appliance failure. Iron treatment where staining is the problem. Softening where stiffness and detergent use are the problem. Carbon where chlorine is the problem. A dedicated laundry filter appliance addresses at most the first of these. Our whole house water filter guide covers how the stages combine for a household with more than one of these complaints.
Questions people ask about water filter for laundry
Will a filter make laundry softer?
No. Stiff grey washing is hardness reacting with detergent, and hardness needs a softener rather than a filter.
What removes orange staining on washing?
Treating the iron in the water, with a softener within its limits or an iron filter above them. Do not use chlorine bleach, which sets the stain.
Does a whole house carbon filter help laundry?
Yes, by removing chlorine, which reduces the smell in towels and bedding and is gentler on fibres and elastic.
Is a laundry specific filter worth buying?
It addresses sediment at best. The complaints people usually have are hardness or iron, which are treated at the point of entry.